Polarization mechanisms of dielectric materials at a binary liquid interface: impacts on electrowetting actuation.

We explored polarization mechanisms at the interface between a dielectric material (an electrolyte) and an insulating liquid, during electrowetting actuation. Native surface charge density due to hydrophobic coating has been measured as an offset voltage for which the contact angle is at its minimum. Surface charge densities as low as 0.023 mC m-2 have been measured using this method, demonstrating that electrowetting can be used as a probe to measure native surface charge density. This effect strongly differs depending on the kind of polarization and is at the origin of major discrepancies between alternative and direct polarization during electrowetting actuation. A new model describing electrowetting actuation is also proposed, leading to a more predictive description as well as useful recommendations on materials to obtain a stable actuation under DC polarization.

Two-liquid wetting properties as a surface polarity probe for hydrophobic coatings.

A model for the spreading of a non-polar liquid on a surface within a polar medium is described theoretically, according to Fowkes, Good and Girifalco approximations on interfacial tension. We demonstrate both theoretically and experimentally that surface polarity measurements using the contact angle of two immiscible liquids minimize drastically the measurement error. The present method has been successfully applied to various substrates of variable polarity and overall surface energy. We also demonstrate that this method allows a direct measurement of surface sensitivity to pH.

Evaluation of chemical treatment on zirconia surface with two primer agents and an alkaline solution on bond strength.

OBJECTIVES: This study evaluated the effect of an alkaline solution and two 10-methacryloyloxydecyl dihydrogen phosphate (MDP)-based primer agents on bond strength to zirconia (yttria-stabilized tetragonal zirconium polycrystal [Y-TZP]) through the shear bond strength (SBS) test. MATERIALS AND METHODS: Sixty square-shaped Y-TZP samples were embedded in an acrylic resin mold, polished, and randomly assigned to one of six groups (n=10) according to treatment surface: group CR, no treatment (control); group NaOH, 0.5 M NaOH; group AP, Alloy Primer; group ZP, Z-Primer Plus; group NaOH-AP, 0.5 M NaOH + Alloy Primer; and group NaOH-ZP, 0.5 M NaOH + Z-Primer Plus. The resin cement (Rely X U100) was applied inside a matrix directly onto the Y-TZP surface, and it was light-cured for 40 seconds. The samples were stored in distilled water at 37°C for 24 hours prior to the test, which was performed in a universal machine at a crosshead-speed of 0.5 mm/min. The data were analyzed by one-way analysis of variance and Tukey tests (p<0.05). Light stereomicroscopy and scanning electron microscopy were used to assess the surface topography and failure mode. RESULTS: The SBS was significantly affected by the chemical treatment (p<0.0001). The AP group displayed the best results, and the use of NaOH did not improve SBS results relative to either AP or ZP. The samples treated with Alloy Primer displayed mainly mixed failures, whereas those conditioned with Z-Primer Plus or with 0.5 M NaOH presented a balanced distribution of adhesive and mixed failure modes. CONCLUSIONS: The use of a NaOH solution may have modified the reactivity of the Y-TZP surface, whereas the employment of a MDP/6-4-vinylbenzyl-n-propyl amino-1,3,5-triazine-2,4-dithione-based primer enhanced the Y-TZP bond strength.

Evaluation of fracture resistance of endodontically treated maxillary premolars, restored with ceromer or heat-pressed ceramic inlays and fixed with dual-resin cements.

The aim of this study was to evaluate the fracture resistance of endodontically maxillary premolars restored with mesio-occlusal-distal (MOD) inlays made with ceramic (IPS-Empress 2) and ceromer (Targis) and luted with three different dual-cured resin cements (Enforce, Variolink II, Panavia F). Sixty maxillary premolars were randomly distributed into six groups, according to their mesio-distal and facio-lingual dimensions. The teeth were endodontically treated and MOD cavities prepared. After the restorations were cemented, the samples were thermocycled and submitted to an axial compressive load by the action of a rounded end steel cylinder contacting the incline planes of occlusal surfaces of the teeth. The mode of fracture was analysed with a microscope. The best results were found with the combinations (cement/restorative material) Enforce/Targis (107.57 kgf) and Enforce/Empress (90.21 kgf) followed by Variolink II/Targis (86.44 kgf)-Variolink II/Empress (84.07 kgf) and Panavia F/Targis (82.43 kgf)-Panavia F/Empress (76.73 kgf). Analysis of variance (P < 0.05) showed a significant difference between Enforce and Panavia cements regardless of the restorative material. Considering the same luting agent there was no statistically significant difference between the restorative materials. Fracture of lingual cusps occurred in 55 of the 60 teeth and most of them were of the cohesive type.

High incidence of adverse reactions to egg challenge on first known exposure in young atopic dermatitis children: predictive value of skin prick test and radioallergosorbent test to egg proteins.

BACKGROUND: Egg skin prick test (SPT) and/or radioallergosorbent test (RAST) positivity has been described in infants and children with a food allergy, or in infants at high risk of atopy who have never eaten eggs. Clinical reactions are also observed when some of these children or infants eat eggs for the first time. OBJECTIVE AND METHOD: A prospective study was made of 107 atopic dermatitis (AD) children (66 boys, 41 girls) aged 1-19 months (median 5 months) who had never ingested egg, to compare the outcome of a first oral egg challenge and the results of albumen and yolk SPTs and RASTs. RESULTS: The egg challenge (conducted at age 12-24 months: mean 16 months, median 15 months) was positive in 72/107 children (67.3%). The reactions were immediate or early (first 6 h) in 56/72 (77.8%). The most severe (all within the first 6 h) were one case of anaphylactic shock (1.4%), three cases of laryngeal oedema (4.1%) and one serious attack of asthma (1.4%). The skin weal diameter at and above which reactions always occurred was 5 mm for both albumen and yolk. They were, however, also observed in the complete absence of a weal. The outcome of the challenge was always positive when the specific IgEs (sIgE) for albumen and yolk were > 99 KU/L and > or = 17.5 KU/L, respectively. Here, too, reactions were noted even when sIgE levels were < 0.35 KU/L. CONCLUSION: AD children who have never eaten eggs may be sensitized and display reactions at the first ingestion. The percentage of reactions in this series was by no means negligible. These findings were observed in children with mild as well as moderate-severe AD when first examined. SPT for albumen and yolk diameter > or = 5 mm, and sIgE for albumen > 99 KU/L and for yolk > or = 17.5 KU/L were 100% specific in predicting the outcome of the challenge. It may thus be concluded that children with AD whose SPT and/or RAST for albumen and/or yolk are equal to or higher than these cut-off values should not be subjected to the oral challenge when consideration is given to the introduction of egg in their diet. Even when these cut-offs are not reached, however, clinical reactions to the challenge cannot be ruled out a priori, and it should be preferably performed in a protected environment, such as a hospital.

[Food intakes in breast-feeding mothers]. / Intakes alimentari in madri nutrici.

BACKGROUND: The relation between mother's diet and breastmilk composition is still an open issue. Nutritional inadequacies during lactation may affect the well-being of both the mother and the infant. For this reason breast feeding women usually pay attention about their alimentary practices and about their style of life during breast-feeding period. This research was conducted to verify the adequacy of lactating mother's diet in comparison with the Italian recommended daily assumption levels of nutrients (LARN 1996) for this category. We have also compared food intake of not breast feeding mothers with the LARN, and analyzed the differences between these groups of mothers. METHODS: Forty-eight healthy infants were selected, 23 bottle fed, 25 breast fed. Mothers's diet in the previous 48 hours was investigated using a structured questionnaire. The data collected were processed using software Dietosystem to obtain the daily nutrient intakes. RESULTS: The wetnurses's diet in comparison with the LARN 1996 resulted hypocaloric and hyperproteic, deficient in Calcium, Iron, folic acid and vitamin E. Surprisingly not breast feeding mothers's intake of nutrients is closer to LARN levels than that of breast feeding mothers. CONCLUSIONS: Mothers are not informed enough about their alimentation during lactating period. Pediatricians must improve their knowledge about this subject and give the mothers the information they need to achieve the recommended food requirements.

Food intakes in a group of breast-feeding and not breast-feeding mothers.

The relation between mother's diet and breast milk composition is still an open question. An important issue is whether mothers who are breast feeding modify, respect to before lactation, food intake to satisfy the increased requirements.

[Use of natural vitamin supplements in children during convalescence and in children with athletic activities]. / Impiego di integratori vitaminici naturali in bambini durante periodi di convalescenza e in bambini che praticano attività sportive.

BACKGROUND AND AIMS: Sporting activities and periods of convalescence call for an added intake of nutrients in children. This study aimed to evaluate the effect of a natural vitamin supplement on diet, food intake, body composition and muscular strength in children during convalescence and in children practising sports. METHODS: A comparative study was performed in two different groups of subjects: 20 children aged between 6 and 12 years old during convalescence following infections of upper airways, and 20 9-year-old children forming part of a football team. All subjects were randomly subdivided into two groups who were respectively given a vitamin supplement (Vitality Roeder 2000 Junior) or a placebo for 4 weeks. Weight, body composition using and muscolar strength using dynamometer measured before and after the study and a food diary was kept for 3 days before each visit. RESULTS: No significant differences in body mass and strength emerged from the data collected in the athletic group, whereas an increase was observed in appetite, calorie intake, weight and muscular strength in the convalescent group (p < 0.05). A significant increase in vitamin B12, B3, B5 and D levels was observed in both groups. CONCLUSIONS: The supplement to provides an adequate intake for those categories at risk of vitamin deficiency or in conditions of increased requirements.

A comparison of bond strengths of complete crowns using two types of cements and three cleaning agents.

This study evaluated the influence of three cleaning agents on the bond strength of complete crowns cemented with zinc phosphate and polycarboxylate cements. For the polycarboxylate cement group, three cleaning agents were used: Tergentol; Tergentol + polyacrylic acid; Tergentol + citric acid. Zinc phosphate cement was used as a control group with Tergentol. There were no statistically significant differences of mean retentive force for either cement regardless of the test conditions. The marginal fit after cementation was also evaluated and the results of zinc polycarboxylate were lower than zinc phosphate cement and were statistically significant.

Neurofibroma plexiforme de laringe en un niño sin enfermedad de Von-Recklinghausen / Larynx plexiform neurofibroma in a child without Von Recklinghausen disease

Se presenta un caso de neurofibroma laringeo y su evolucion despues del tratamiento. Se hace una revision de la literatura mundial. Se trata de un nino de 3 años de edad, quien desde el periodo neonatal presenta obstruccion laringea progresiva hasta presentar un cuadro obstructivo agudo al momento de su consulta, requiriendo traqueostomia. Se practicó laringoscopia directa y biopsia de una masa lisa, redondeada, submucosa que ocupa el repliegue ariepiglotico y aritenoides izquierdo, con resultado de neurofibroma con degeneracion mixoide. Se extirpa el tumor mediante faringotomia infrahioidea y se obtiene un diagnostico definitivo de neurofibroma plexiforme de laringe. El paciente evoluciona satisfactoriamente sin evidencias hasta la presente de recidivas. No se encontraron estigmas de la enfermedad de Von Recklinghausen ni antecedentes familiares de esta enfermedad. Los tumores neurogenicos de la laringe son muy raros en nuestro medio como en el resto del mundo segun la literatura medica

Nebulized glucagon in the treatment of bronchospasm in asthmatic patients.

This study sought to determine if nebulized glucagon, a well-known smooth muscle relaxant, is effective in relieving asthmatic bronchospasm. Ten subjects, aged 12 to 26 years, with chronic stable asthma were studied in a pulmonary function laboratory under a randomized double-blind, placebo-controlled, crossover design. Bronchospasm was induced in each subject with progressive doses of nebulized methacholine until forced expiratory volume in 1 second (FEV1) had decreased at least 20% from baseline. Subjects then received either nebulized saline or 2 mg of nebulized glucagon. Spirometry was performed at 5, 15, and 30 minutes after treatment. Subjects then received 2.5 mg of nebulized albuterol and had spirometry 15 and 30 minutes thereafter. Each subject returned for testing with the alternative solution at least 1 week later. Treatment with nebulized glucagon resulted in a 58% +/- 15% improvement in FEV1 15 minutes after treatment compared with 36% +/- 7% after nebulized saline (P < .05). No adverse effects of glucagon treatment occurred. This study suggests that nebulized glucagon reduces methacholine-induced bronchospasm in asthmatic patients.

Influence of different metal restorations bonded with resin on fracture resistance of endodontically treated maxillary premolars.

STATEMENT OF PROBLEM: Fracture of endodontically treated teeth has been of great interest because it is a common clinical occurrence. PURPOSE OF STUDY: This research evaluated the fracture resistance of endodontically treated first maxillary premolars restored with different metal restorations and bonded with Panavia Ex resin. MATERIAL AND METHODS: Fifty teeth were randomly divided into five groups with MOD tooth preparation: (1) inlay with an isthmus width of one third the intercuspal distance for a silver amalgam restoration (negative control), (2) inlay with an isthmus width equal to that in group 1, (3) inlay with an isthmus width of half the intercuspal distance, (4) equal to group 3 with lingual and proximal preparation, and (5) onlay (positive control). The cast restorations of groups 2, 3, and 4 were bonded with Panavia Ex resin and those from group 5 cemented with zinc phosphate cement. Samples were restored and subjected to thermocycling, and the teeth were submitted to an axial compressive force. RESULTS: The cast inlay restorations that bonded with Panavia Ex resin significantly elevated the fracture resistance of endodontically treated maxillary premolars compared with the silver amalgam restorations. However, teeth restored with cast onlay restorations cemented with zinc phosphate cements recorded the best results. CONCLUSION: The increase of fracture resistance by MOD inlay cast restoration bonded with Panavia Ex resin suggested valid clinical application within the conditions of this study.

Primer hallazgo de toxoplasma Gondii en un bovino del estado Yaracuy, Venezuela / First finding of toxoplasma Gondii from a bovine of the Yaracuy State, Venezuela

Se logro el aislamiento de Toxoplasma gondii en una muestra de diafragma de un bovino clínicamente sano, sacrificado para ser destinado al consumo de la población en el Matadero Industrial Centro Occidental de Barquisimeto, estado Lara. La muestra fue inoculada en ratones blancos los cuales se dejaron en observación durante 30 días, al final de este período se inoculó otro lote de ratones, lográndose el aislamiento 7 días después del pasaje. con esto se confirma la infección inaparente por T.gondii en la especie bivina en Venezuela

Grazing incidence Czerny-Turner monochromator utilizing sagittal focusing mirrors.

A new soft x-ray monochromator design, especially conceived for high brightness undulator radiation, is discussed. Its aim is to achieve a resolution limited only by grating figuring slope errors, together with a simple grating rotation scanning; thereby operating with fixed entrance and exit slits. Three cylindrical optical surfaces are employed between the slits, including two mirrors focusing in their sagittal planes, and a resolution lambda/Deltalambda up to approximately 14000 at the carbon K-edge is predicted. Its implementation for the planned Trieste synchrotron radiation facility is described in detail.

[Centric registration relation in dentate patients using bilateral manipulation--comparative analysis of three techniques]. / Estudo do registro da relação cêntrica em pacientes dentados utilizando a manipulação bilateral--análise comparativa de três técnicas.

Three techniques of centric relation registration were compared using the "Jig" (LUCIA), the "Leaf-Gauge" (LONG JUNIOR) and an wax anterior guide. The casts were mounted and analysed in a Whip-Mix articulador. The results permitted to conclude that, from the statistical viewpoint, did not occurred significant differences among techniques and centric relation occurred in an area not in a point. Because of facility and quickness the technique advocated by LON JUNIOR is recommended.

[Negative carving: clinical applications]. / Escultura negativa: aplicação clinica.

The objective of the negative carving technique is to develop properly the occlusal principles during fabrication of occlusal surfaces of temporary crowns or metalhi restorations.